10c - adfToPlainMarkdown and plainMarkdownToAdf exported, whitespace-only leaves trimmed at a line end

src/conformance/adf-property.test.ts

@@ -4,10 +4,21 @@ import test from 'node:test'
 
 import { adfDocument, propertyRuns, propertyTimeout } from './property-harness.ts'
 import { adfToMarkdown } from '../markdown/emit/adf-to-markdown.ts'
+import { adfToPlainMarkdown } from '../markdown/emit/plain-reduction.ts'
+import { directivePrefix } from '../markdown/directive-syntax.ts'
 import { markdownToAdf } from '../markdown/parse/markdown-to-adf.ts'
+import { plainMarkdownToAdf } from '../markdown/parse/plain-lift.ts'
 import { toEditorNormal } from '../adf/editor-normal.ts'
 
 const gateRuns = 1600
+const renamedPrefix = '!adg:'
+
+// Renaming the prefix changes what markdown reads only where a directive was read.
+function readsNoDirective(markdown: string): boolean {
+  const read = markdownToAdf(markdown)
+  const renamed = markdownToAdf(markdown.replaceAll(directivePrefix, renamedPrefix))
+  return read.ok && renamed.ok && JSON.stringify(read.value).replaceAll(directivePrefix, renamedPrefix) === JSON.stringify(renamed.value)
+}
 
 test('a generated document refuses to emit, or its markdown reads back to it', { timeout: propertyTimeout }, () => {
   fc.assert(
@@ -21,3 +32,17 @@ test('a generated document refuses to emit, or its markdown reads back to it', {
     propertyRuns(gateRuns),
   )
 })
+
+test('a generated document writes plain markdown refusing only what the guard refuses, and that markdown reads back to itself', { timeout: propertyTimeout }, () => {
+  fc.assert(
+    fc.property(adfDocument, (document) => {
+      const written = adfToPlainMarkdown(document)
+      assert.ok(written.ok, written.ok ? '' : `${written.error.code}: ${written.error.message}`)
+      assert.ok(readsNoDirective(written.value), `a directive in ${JSON.stringify(written.value)}`)
+      const read = plainMarkdownToAdf(written.value)
+      assert.ok(read.ok, read.ok ? '' : `${read.error.code}: ${read.error.message} — reading ${JSON.stringify(written.value)}`)
+      assert.deepEqual(adfToPlainMarkdown(read.value), written, `reading ${JSON.stringify(written.value)}`)
+    }),
+    propertyRuns(gateRuns),
+  )
+})